The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory captions and links exemplifying features within the Earth system. The community is invited to contribute digital imagery, short captions and relevant links.

Ice on Utah Lake

This photo shows randomly oriented elliptical openings in the ice of mostly frozen Utah Lake in northern Utah. It was taken through the open window of a small aircraft flying approximately 1,000 m above the surface on December 27, 2011. Note that despite the orientation of the openings, the biggest has a major axis of perhaps 20 m in length; pale triangles have formed on their lower ends, which are more or less facing the same direction. The apexes of the triangles are pointed toward the southeast -- north is at right. This gives a clue as to their origins; deposits of spray across the open water from northwest winds.

A number of factors likely come into play to determine the teardrop shape, size and orientation of these holes, including strength, persistence and direction of the wind and the thickness and compression and tension of the ice. Moreover, because Utah Lake is shallow, average depth is about 3 m, strong winds can stir up bottom sediments, which will ultimately affect surface conditions and freeze-up rates. As winter wears on, the holes eventually freeze over, and the lake ice becomes so thick that small aircraft looking for the nearby airport when visibility is poor have been known to mistakenly land on the completely frozen lake surface.